Polypropylene glycols and substituted polypropylene glycols are used in conjunction with crosslinking agents to produce durable press fabrics with improved soil release performance

ABSTRACT

THIS INVENTION RELATES TO FABRICS TREATED WITH ONE BATH SYSTEMS CONTAINING CROSSLINKING AGENTS AND POLYPROYLENE ALCOHOLS, GLYCOLS AND POLYOLS. THESE TREATMENTS ONCE APPLIED TO FABRICS PRODUCE FABRICS WITH WASH-WEAR AND DURABLE PRESS PERFORMANCE AND WHICH HAVE IMPROVED SOIL RELEASE CHARACTERISTICS. THIS PROVIDES GARMENTS FOR THE CONSUMER WITH BETTER WASHABILITY CHARACTERISTICS. THESE TREATMENTS ARE MOST EFFECTIVE ON ALL-COTTON FABRICS BUT THEY MAY ALSO BE APPLIED TO POLYESTER-COTTON BLENDS. THE SYSTEM UTILIZED TO ACHIEVE SOIL-RELEASE IS A ONE BATH SYSTEM READILY APPLICABLE TO EITHER PRECURED OR POSTCURED FABRICS. THESE TREATMENTS HAVE BEEN EVALUATED USING SOILING TEST FOLLOWED BY LAUNDERING AND MEASURING REFLECTANCE VALUES.

Robert J. Harper, Jr., Metairie, Joseph S.

United States Patent Office 3,676,052 POLYPROPYLENE GLYCOLS AND SUBSTITUTED POLYPROPYLENE GLYCOLS ARE USED IN CON- JUNCTION WITH CROSSLINKING AGENTS TO PRODUCE DURABLE PRESS FABRICS WITH IMPROVED SOIL RELEASE PERFORMANCE Bruno, Chalmette, and Gloria A. Gautreaux, Metairie, La., assignors to the United States of America as represented by the Secretary of Agriculture No Drawing. Filed Nov. 3, 1969, Ser. No. 873,703 Int. Cl. D06m /10, 15/54, 15/58 U.S. Cl. 8115.6 4 Claims ABSTRACT OF THE DISCLOSURE This invention relates to fabrics treated with one bath systems containing crosslinking agents and polypropylene alcohols, glycols and polyols. These treatments once applied to fabrics produce fabrics with wash-wear and durable press performance and which have improved soil release characteristics. This provides garments for the consumer with better washability characteristics. These treatments are most effective on all-cotton fabrics but they may also be applied to polyester-cotton blends. The system utilized to achieve soil-release is a one bath system readily applicable to either precured or postcured fabrics. These treatments have been evaluated using soiling tests followed by laundering and measuring reflectance values.

In addition to their role as soil release agents, these polypropylene glycols also have been found to be effective in improving the absorption of optical brighteners during laundering by durable press fabrics. This property can be readily observed in the improved whiteness after multiple washings of the fabrics so treated as well as by the appearance of these fabrics under ultraviolet light.

Finally, a combination soil release finish has been applied to fabric using polypropylene glycols and carboxymethylcellulose in the same finishing bath.

A non-exclusive, irrevocable, royalty-free license in the invention herein described, throughout the world for all purposes of the United States Government, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

This invention relates to treatments which impart wrinkle resistance to cellulose textile materials. In particular, it relates to providing a method by which cotton fabrics may be finished so that they will be wrinkle resistant and will have improved soil release characteristics. These improved soil release characteristics impart better washability to the final durable press garment. This is an added advantage to the consumer, who is frequently faced with the problem of removing soil stains from durable press garments.

This soil release finish can be achieved by the addition of polypropylene glycol or a modified polypropylene glycol to the crosslinking solution used to produce durable press garments. This permits easy application in either precured or postcured durable press fabrics.

Heretofore, it is well known that normally crosslinked durable press or wash-wear fabrics do not have acceptable soil release characteristics. This lack of a soil release finish causes the consumer problems when he or she attempts to remove stains by a normal laundering procedure. While certain agents have been devised to improve the soil release characteristics, these agents are usually polymeric acids or salts of acids. The use of polymeric acid or charged moieties may cause problems in finishing because of their elfect on metal salt catalysts and other sensitive 3,676,052 Patented July 11, 1972 components in crosslinking baths. Typical problems may arise from several sources. First, the charge particle may interfere with the action of the metal salt catalyst in producing sufiicient crosslinking for acceptable smooth drying properties. Second, the polymeric acids are slow and difficult to solubilize and sometimes either themselves or the other bath components are precipitated by the metal catalyst or low pH values necessary for certain crosslinking agents. Finally, high molecular weight polymeric additives may have a stiffening effect on fabric hand. This can cause loss of resiliency in heavy or tightly woven fabrics and undesirable stiffness.

We have now found that by incorporating certain amounts of polypropylene glycols or substituted propylene glycols in the pad bath, it is possible to produce durable press or wash-wear fabrics with improved soil-release characteristics. The ready solubility and non-ionic nature of these materials permits facile use of these materials in crosslinking baths. Their low molecular weight permits deep penetration into the fiber or fabric thus helping the washability of deep stain. Finally, the polyglycols tend to be inherently cheaper than polyacids such as carboxymethylcellulose.

Since these polypropylene glycol are reactive with crosslin'king agents, they are permanently bound to the cotton through the crosslinking agent. As such, they are retained through numerous washings. Soiling tests have been run after the initial wash as well as many washes later. The advantages in the use of these additives are clearly demonstrated by reflectance measurements of the fabrics after being soiled and laundered. In all cases, the fabrics treated with crosslinking agent and the polypropylene glycol had a higher reflectance reading than the fabric treated with crosslinking agent only.

In addition to the reflectance readings, the effectiveness of these compounds is readily observed by a visual inspection of the soiled fabric. In general, the crosslinked controls appear visually darker after being soiled and Washed. Reflectance measurements provide a method of placing a. numerical value on the relative effectiveness of the various treatments.

In addition to their effectiveness as soil release agents, these materials also are effective in improving the absorption of optical brighteners by the fabric from the laundry detergent. This improvement is important because the failure of crosslinked cotton to absorb optical brighteners leads to a graying and yellowing on long term use. It can be readily demonstrated that these polypropylene glycols are effective in this regard by inspecting the fabrics under ultraviolet light. The sample treated with polypropylene glycol and crosslinking agent is readily observed to be lighter than the fabric treated with crosslinking agent only.

In general terms, the process of this invention is the incorporation of polypropylene glycols or substituted polypropylene glycols in normal pad bath solutions used to produce wash-wear or durable press cotton. From this point on, the fabric is finished in a standard manner according to contemporary textile practice. This method can be used with a number of textile formulations, the only requirement being that a certain amount of water be rcplaced with an equivalent amount of polypropylene glycol. The method is readily applicable to either precure or postcure, one bath, one step treatments. The solubility of the polypropylene glycols limits the use either to water soluble or water dispersible molecular weights. Application of water insoluble polypropylene glycols can also be used but care must be taken to use a nonsoiling emulsification agent. This type of application is readily applicable to either precure or postcure systems, the only requirement being that the garment be fabricated between the drying and curing step.

3 DESCRIPTION OF AGENTS Polypropylene glycols (A) in a molecular weight range up to 2,000 have been demonstrated to impart durable soil release characteristics to permanent press fabrics. These fabrics also have been shown to possess improved absorption characteristics for optical brighteners as well. The preferred molecular weight range appears to be from 100 to the limit of water solubility (100-700).

(A) HOOHQ(CHCHSO CHZ)BCIH CH3 In addition to the straight polypropylene glycols, the polymerization of propylene oxide on a glycol, triol, or polyol base may also be utilized. In this application, a variety of base polyols may be utilized but for example purposes (B) and (C) may be considered representative.

( X,Y,Z= to 25.

Ltl

Lil.

Example (B) is produced by condensing propylene glycol on a glycerol base and Example (C) is produced by the condensing propylene oxide on a pentaerythritol base. Another possible starting polyol is sorbitol. In this case, the product is Example (D),

(D) CH OR where (E) CH3 CH3 This represents another modification of the type illustrated for the basic polymer system. The only limitation should be that this substitution does not increase oleophilic characteristics of the total molecules too much.

CONCENTRATION OF AGENT IN PAD- BATH SOLUTION While from about 0.1% to 15% of polypropylene glycols have been shown to be effective in improving the soil release properties of durable press cottons, the optimum amount of additive (based on reflectance measurements) appears to be from about 1% to about 5% of the polypropylene glycol additive in the pad bath.

With the very high amounts of polypropylene glycols, the ability of the fabric to absorb optical brightener continues to improve with increasing add-ons. However, because soil release properties are better at intermediate addons, the finisher must decide which property is to be utilized. If soil-release treatments are to be emphasized, the intermediate level of polyoxypropylene glycol should be used. If optical brightener absorption is to be emphasized, larger quantities of polypropylene glycol should be utilized.

The following examples are intended to be representative of treating solutions and methods rather than limiting. Numerous variations are possible for anyone practiced in the textile art.

Example 1 Cotton printcloth was padded with a solution containing 20% Permafresh 183K (9.0% dimethylol dihydroxyethyleneurea), 3% modified zinc nitrate, and 4% polypropylene glycol (mol wt. 550); polyoxypropylene grafted onto pentaerythritol (herein referred to as PEP-550). A control sample was prepared by padding the fabric with a similar solution without any polypropylene glycol additive. The samples were dried for 10 minutes at 60 C. and cured for 15 minutes, at C. Both samples and untreated printcloth were then laundered.

A soiling solution was prepared from a dispersion of carbon black in mineral oil and this diluted with carbon tetrachloride.

The two treated samples and the untreated cotton printcloth were then soiled by dipping the fabrics into the soiling mixture, drying, and then washing and drying under normal laundry conditions. At this point, multiple reflectance readings were taken. The average reflectance reading of the PEP-550 treated sample was 61.0, the value for the crosslinked control was 55.0, and the value for the untreated control was 56.4. It is well known that in a comparative series of samples so treated, the least soiled sample will have the highest reflectance value. This indeed was the case since the sample with the highest reflectance value was visually the least soiled of the group.

The permanent nature of the treatment was demonstrated by washing unsoiled samples of the above fabrics for seven times under normal laundry conditions. The samples were then soiled as in the prior case. The sample treated with the PEP-550 had a reflectance value of 72.6, the crosslinked control had a reflectance value of 62.6 and the untreated printcloth had a value of 62.6. The sample treated with the PEP-550 by visual inspection was obviously less soiled than the crosslinked cotton control (which had a lower reflectance reading).

Example 2 This sample demonstrates the use of varying concentrations of polypropylene glycol, PEP-550, in a crosslinking bath. Cotton printcloth was padded with 20/ Permafresh 183K (9.0% dimethylol dihydroxyethyleneurea), 3% modified zinc nitrate catalyst and varying amounts of PEP-550 (see Example 1 for composition). After curing as in Example 1, the fabric was washed, dried, soiled, and relaundered. Reflectance readings were then made.

Con-

Refleetditlone W/W Additive ance W RA rating 2% PEP550. 58. 8 291 5. 3% PEP-550"- 58. 5 292 4. 5 5% PEP-550... 61. 4 285 4. 7 PEP-550 47. 6 274 4. 7 crosslinked control, no additive 40. 9 300 4. 7 Untreated cotton 38. 9 187 1. 5

Reflectance Additive: (7 wash cycles) 2% PEP-550 70.1

3% PEP-550 70.5

5% PEP-550 71. 6 10% PEP-550 68.5

No additive, crosslinked control 65.3 Untreated cotton 63.9

These results demonstrate the permanent nature of the improvement from these additives with respect to soil release performance. This same series of samples was also inspected under ultraviolet light. The untreated cotton was the lightest under ultraviolet light and the crosslinked control was a dark grey. The samples treated with the PEP-550 were intermediate in shade but became progressively lighter with higher polymer applications. Thus, to maximize the improvement due to absorption of optical brightener, the highest polymer add-ons should be used. However, even with the lower add-ons, the improvement in optical brightener absorption is easily observed under an ultraviolet light. From inspection of unsoiled samples, the samples which absorb optical whitener appear whiter than the crosslinked control.

Example 3 Cotton printcloth was padded with a solution containing Permafresh 183K (9.0% dimethylol dihydroxyethyleneurea), 3% modified zinc nitrate catalyst, and 5% polypropylene glycol grafted onto glycerol (herein referred to as TP-340). A control sample was prepared by padding the fabric with a similar solution Without any polypropylene glycol additive. The samples were dried for 10 minutes at 60 C. and cured for 15 minutes at 130 C. These two samples and an untreated cotton were then laundered seven times. The samples were soiled as in Example 1 and relaundered. The sample treated with polypropylene glycol (TP-340) had an average reflectance value of 70.8. The crosslinked control had a reflectance value of 65.3 and an untreated control had a reflectance of 63.9.

Example 4 Cotton printcloth was padded with a solution containing 18% Permafresh 183K (8.1% dimethylol dihydroxyethyleneurea), 3% modified zinc nitrate catalyst, and 5% dipropylene glycol monomethylether. A control sample was prepared by padding the fabric with a similar solution without any polypropylene alcohol additive. The samples were dried for 10 minutes at 60 C. and cured for 15 minutes at 130 C. These two samples and an untreated cotton were then laundered, soiled and relaundered. The sample treated with propyleneglycol monomethylether had a reflectance value of 64.9 compared to a value of 50.0 for the crosslinked control and to a value of 51.6 for untreated cotton. Unsoiled samples of the same fabrics were washed 10 times, soiled and relaundered. The sample treated with dipropyleneglycol monomethylether had a reflectance value of 62.6, the crosslinked control had a reflectance value of 60.0 and the untreated cotton had a reflectance value of 49.9. Both these results show that an improvement in soil release can be realized by the use of the dipropyleneglycol monomethylether.

Example 5 A white cotton denim was padded with a solution containing 18% Permafresh 183K, 3% modified zinc nitrate catalyst, and 20% polypropylene glycol (molecular wt. 425; referred to as PPG-425). A control fabric was padded with the same formulation without polypropylene glycol. Both fabrics were dried for 10 minutes at 60 C., fabricated into sample trouser cuffs, pressed, and cured for 15 minutes at C. Both cufis were laundered for 30 times and then inspected under ultraviolet light. The sample treated with polypropylene glycol appeared whiter under ultraviolet light than the control. This demonstrates the ability of the polypropyl glycols to enhance the ability of durable press fabrics to absorb optical brighteners.

Example 6 Cotton printcloth was padded with a sample containing 20% Permafresh 183K (9% dimethylol dihydroxyethyleneurea), 3% modified zinc nitrate catalyst, 5% PEP-450 (see Example 1 for composition; molecular weight of 450) and 1% carboxymethylcellulose. A second sample was treated with 20% Permafresh 183K (9% dimethylol dihydroxyethyleneurea), 3 modified zinc nitrate catalyst and 5% PEP450. A third sample was treated with 20% Permafresh 183K (9% dimethylol dihydroxyethyleneurea), 3% modified zinc nitrate catalyst and 1% carboxymethylcellulose. Another sample was treated with 20% Permafresh 183K and 3% modified zinc nitrate catalyst. All samples were dried and cured as in the earlier examples. These fabrics and untreated cotton were laundered, soiled, and relaundered. The reflectance readings of all samples were then taken. The same untreated fabrics were also washed 7 times, soiled, and relaundered. Reflectance readings of all samples were then taken.

Reflectance readings Additive 1st wash 7th wash 5% PEP-450; 1% CMC 78.0 76. 3 5% P P-45 76.5 73.5 1% CMC. 77.5 74.4 No additive (crosslinked cotton). 55.0 62.6 Untreated eotton 56. 4 62. 6

These results show that the combination of additives produces higher reflectance values and better soil release appearance than does a treatment with a single agent only. Of course, either the double agent or the single additive agent (either polypropylene glycol or carboxymethylcellulose alone) is considerably better than the crosslinking treatment with no additive agent at all.

Example 7 3 TP-340 69. 67. 0 5 00% TP-340. 70. 1 69. 6 Crosslinked (no add 52. 6 49. 4 Untreated cotton 58. 4 51. 5

These results show that while optimum results can be achieved with 3 to 5% of the polypropylene glycol, a noticeable measurable improvement can be achieved with as low an add-on as 0.1% of polypropylene glycol additive. In addition to its soil release properties, the samples treated with TP-34O showed more improved absorption of ultraviolet light than the crosslinked control. It should be noted that the improvement realized from the use of polypropylene glycols is readily apparent from reflectance readings after the seventh wash as well as after the first wash, thus demonstrating the permanent nature of this improvement.

Example 8 This example is the same as Example 7 except that a varied concentration of a polyoxypropylene polyol produced by grafting propyleneoxide onto a sorbitol ring (molecular weight approximately 760, herein referred to as SP-760) were used with crosslinking agent. In particular, the concentration of polyol was varied from 0.5% to 5% of SP760 with 18% of Permafresh 183K (8.1% DMHEU) and 3% of modified zinc nitrate catalyst. After the samples had been padded, dried, and cured as in Example 7, they were laundered, soiled, and relaundered. Reflectance measurements were then performed.

Reflectance Additive: (after 1 wash) 0.5% SP-760 56.3 1.0% SP-760 65.9 3.0% SP-760 66.5 5.0% SP-760 66.4 Treated control, no additive 50.6 Untreated control 53.8

These results show that while improvement can be achieved with less than one percent additive, the optimum improvement can be achieved by the use of 1 to 5% of the sorbitol based polyoxypropylene polyol.

Example 9 Reflectance readings 7th wash Additive 1st wash 3% TP-340 49. 8 41. 0 No additive (crosslinked control) 45. 1 35. 5 Untreated polyester cotton. 45. 3 31. 9

Example 10 This example relates to the use of polyoxypropylenetetrol (PEP-450) with crosslinking agent (see earlier example for description of this agent) and a polyethylene softener in a crosslinking formulation. In this test, three fabrics were used. One was a cotton printcloth, the second was a 50-50 blend of cotton and polyester and the final was a 65-35 polyester cotton blend. A sample of each fabric was padded with a formulation containing 18% Permafresh 183K (8.1% dimethylol dihydroxyethyleneurea), 3% modified zinc nitrate catalyst, 0.5% polyethylene and 5% PEP-450. The other sample of each fabric was treated with the same formulation Without PEP-450. After the fabrics were dried and cured one sample of each fabric was washed one time and a second sample was washed seven times. All fabrics were then soiled and relaundered. Reflectance measurements of each sample were then made.

Reflective readings 1st 7th Fabric Additive wash wash CottoiL. 5% PEP-450 52.5 49.0 Do None 38.3 39.6 Do.-. Untreated fabric" 52.6 54.8 50% polyester, 50% cotton. 5% PEP-450 47. 8 43. 8 Do None 41.5 39.3 D0 Untreated fabric..- 54.5 52.1 65% polyester, 35% cotton 5% PEP-450 50. 1 50. 1 Do None 45.4 43.8 Untreated fabrlc 34.0 38.9

These results indicate that the addition of polyoxypropylenetetrol can be used to improve the soil release properties of cotton and blended fabrics treated with a crosslinking agent and a polyethylene softener. These results indicate that this type of treatment is more effective on all cotton than with blended goods.

In summary, the instant invention can be best described as a process for imparting the qualities of improved soil release performance and absorption of optical brighteners to wash-wear and durable press cotton fabrics and to polyester-cotton blended fabrics, comprising:

(a) impregnating the cotton or other cellulosic fiber with an aqueous solution containing about from 1% to 15% of a crosslinking agent, about from 0.1% to 5% of an acid type catalyst, and about from 0.1% to 20% of a polypropylene polyol or a polypropylene glycol as a reactive additive,

(b) drying the wet impregnated fabric for about from 5 minutes to 24 hours at temperatures about from 25 to 70 C., and

(c) curing the dry impregnated fabric for about from 30 seconds to 20 minutes at temperatures about from C. to C.

We claim:

1. A process for imparting the qualities of improved soil release performance and absorption of optical brighteners to wash-wear and durable press cotton fabrics and to polyester-cotton blended fabrics, comprising:

(a) impregnating the cotton or other cellulosic fabric with an aqueous solution containing about from 1% to 15% of a crosslinking agent, about from 0.1% to 5% of an acid type catalyst, and about from 0.1% to 20% of a reactive alcohol additive selected from the group consisting of:

(1) polypropylene tetrol, made by grafting propylene oxide onto pentaerythritol, and represented where w, x, y, z, =0 to 25 and;

(2) polypropylene hexol, made by grafting propylene oxide onto sorbitol, and represented by the general formula:

CIJHQOR H(|30R 30-0-11 H-o-OR H(|JOR CHzOR where CH3 R= cH,-( :H),H

and X may be varied from 0 to depending on on the moiety employed; (b) drying the wet impregnated fabric for about from 5 minutes to 24 hours at temperatures about from C. to C., and (c) curing the dry impregnated fabric for about from 30 seconds to 20 minutes at temperatures about from C. to C.

2. The process of claim 1 when the said reactive alcohol additives are used in combination with polyethylene as a softener.

References Cited UNITED STATES PATENTS Tesoro et al 8116.3 Prick et a1. 8115.6 Tovey 8116.3 Smith.

Tesoro 8-115.6 Mauldin 8115.6

GEORGE F. LESMES, Primary Examiner J. S. CANNON, Assistant Examiner U.S. Cl. X.R.

8116.3, 115.7, 31, 100, 21 C, 1 W, Dig. 4; 38144; 

